def target = 'How now brown ${animal}. The ${role} has oddly-shaped ${bodyPart}.'
println target.replaceAll(/\$\{([^{}]*)\}/, '?')

def lst = new ArrayList<>();
def m = target =~ /\$\{([^{}]*)\}/
(0..<m.count).each { lst.add(m[it][1]) }
println lst